I think Carol has also mentioned elsewhere that it's OK when you keep your filter from the Q tank running on your main tank, so that when you need the Q tank, all you have to do is to fill the Q tank with water and transfer that filter from the main tank to the Q tank. Carol, which is better: keeping the Q tank filter running on the main tank OR keeping the Q tank cycled with some fish?

I prefer to keep the "Q" tank filter running on the main tank to keep it cycled. Then I can put the empty tank away until I need it. But not all people can stand an empty tank around so keep a fish or two in it to keep it cycle ;D Carol

so if you keep that filter running on a another tank it would be ok to put the q tank empty then fill it up with water when you need it?how long would it have to run until it would be safe to put a fish in?